Evoked response potentials ERP are standard neurophysiological tools or functional diagnostic and investigation of human sensory and motor functions. For these purpose simple but precisely quantified stimuli are used. This simple but useful technique can be also used in cognitive neurophysiology trying to explain how sensed stimuli are not only perceived but also processed and analyzed. This application also requires precise but complex sensory stimulation. For these purposes a special multimodal stimulator for complex visual and auditory stimulation was made. The primary idea was to construct a stimulator, which can present a number of different categories of stimuli in complex spatiotemporal relationship. Also, the patient reaction should be controlled and depending on the detected reactions the specific feedback to the patient should be possible. The precise stimuli timing as well as stimuli synchronization with external devices such as evoked potential averagers should be obtained. The constructed simulator can manage 32 different stimulus categories where' each category assumes a number of complex stimuli sequences. Each stimuli sequence can he build up of either image or textual stimuli defined by its size, position and display time. It can be combined with simultaneously presented auditory stimuli, reproduction of recorded sound file, defined by its side ear of auditory stimuli, reproduction of recorded sound file, defined by its side (ear) of presentation, intensities and duration time. Each category assumes a number of stimuli sequences having the same contextual meaning. Presentation timing of l slin1uJi category arc controlled by PC, on which the stimulator is based, while for other 16 the appearance depends on external events coming from external devices, evoked potential averagers or patient reactions actuators. Stimuli presentation for each stimuli category can be either random – by randomly selecting presentation of one stimuli sequence, sequential – by sequentional displaying of stimuli sequences or simultaneous – presentation of all defined sequences at once and ending of each sequence according to its display/play time. Stimuli category appearance can also be random by defining the density of stimuli category appearance, sequential according to predefined stimuli list and conditional where a next stimulus depends on the patient reaction to the current stimuli. Stimuli a next stimulus depends on the patient reaction to the current stimuli. Stimuli Patient reactions are also analyzed. They are classified as good, wrong, missing, fast and slow responses. Database includes patient data, stimulation tests and test records as well as statistical analysis.